Apparatus, system, and method for providing an implantable ring for altering a shape of the cornea

ABSTRACT

An apparatus, system and method for constricting a cornea of a human eye are disclosed. A control device external to the subject eye, such as an induction generator, may be configured to create a stimulus, such as a magnetic field, for an implanted ring that, when stimulated, may change the curvature, and thus the dioptric power, of the eye, thereby approximating natural accommodation.

CROSS-REFERENCED TO RELATED APPLICATIONS

This application claims priority to U.S. provisional application No.61/784,226 filed on Mar. 14, 2013, the entire contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The instant disclosure relates to implantable devices, and, moreparticularly, to an apparatus, system, and method for providing animplantable ring for altering a shape of the cornea.

BACKGROUND OF THE INVENTION

Surgery on the human eye has become commonplace in recent years. Manypatients pursue eye surgery as an elective procedure in order to avoidthe use of contacts or glasses, while other patients find it necessaryto pursue surgery to correct an adverse condition in the eye. Suchadverse conditions may include, for example, cataracts. A cataractincreases the opacity of the natural lens of the eye, causing impairedvision or blindness. Correction may be achieved by surgically removing acloudy or diseased lens in the patient's eye and replacing it with anartificial lens, known as an intraocular lens (IOL).

The anatomy and physiology of the human eye is well understood.Generally speaking, the structure of the human eye includes an outerlayer formed of two parts, namely the cornea and the sclera. The middlelayer of the eye includes the iris, the choroid, and the ciliary body.The inner layer of the eye includes the retina. The eye also includes,physically associated with the middle layer, a crystalline lens that iscontained within an elastic capsule, referred to herein as the lenscapsule, or capsular bag.

Image formation in the eye occurs by entry of image-forming light to theeye through the cornea, and refraction by the cornea and the crystallinelens to focus the image-forming light on the retina. The retina providesthe light sensitive tissue of the eye.

Functionally, the cornea has a greater, and generally constant, opticalpower in comparison to the crystalline lens. The power of thecrystalline lens, while smaller than that of the cornea, may be changedwhen the eye needs to focus at different distances. This change, or“accommodation,” is achieved by changing the shape of the crystallinelens. Accommodation, as used herein, includes the making of a change inthe focus of the eye for different distances. For example, in order tochange the shape of the crystalline lens for accommodation, the ciliarymuscles may relax to cause ligaments (zonules) that support thecrystalline lens to relax, thereby allowing the crystalline lens tobecome more rounded.

The iris operates to change the aperture size of the eye. Morespecifically, the diameter of the incoming light beam is controlled bythe iris, which forms the aperture stop of the eye, and the ciliarymuscles may contract, as referenced above, to provide accommodation inconjunction with any needed change in the size of the aperture providedby the iris. The opening, or aperture, in the iris is called the pupil.

Correction of defects or degradation in the aspects of the eye may occursurgically, as mentioned above, or non-surgically. In a simple example,it is common to wear glasses or contact lenses to improve vision bycorrecting myopic (near-sighted), hyperopic (far-sighted) and astigmaticeyesight. Rather than relying on glasses or contacts, elective laserrefractive surgery, or other eye surgery, may serve to improve therefractive state of the eye, and may thereby decrease or eliminatedependence on glasses or contact lenses. Additional surgeries mayinclude various methods of surgical remodeling of the cornea, orcataract surgery, for example.

Presbyopia, referenced above, is an adverse condition in which the eyeloses the ability to accommodate. Presbyopia is one of the adverseconditions of the eye for which the aforementioned surgical andnon-surgical treatments have proven relatively successful. However, manyof the aforementioned treatments, such as those in which eye-glasses andcontact lenses are employed, provide only temporary solutions foradverse eye conditions and particularly for adverse eye conditions suchas presbyopia that cause a loss of capability for accommodation.

In other, non-ocular medical fields, in order to provide a morelong-lasting solution for biologic adversities, externally controllabletreatments, such as ionic polymer-metal composites, have recently beenexplored as possible treatment options. For example, these compositeshave been explored for use with artificial limbs and/or limbs that lacksufficient muscular and/or nervous system control or strength.

Accordingly, it may be advantageous to employ the use of externallycontrollable treatments, such as ionic polymer-metal composites, to theeye, and, in particular, to the cornea. Such a solution may provideanother, potentially more viable and long term solution to thecorrection of adverse eye conditions, such as presbyopia, by allowingfor alteration of a shape of the cornea.

SUMMARY OF THE INVENTION

An apparatus, system and method for constricting a cornea of a human eyeare disclosed. A control device external to the subject eye, such as aninduction generator, may be configured to create a stimulus, such as amagnetic field, for an implanted ring that, when stimulated, may changethe curvature, and thus the dioptric power, of the eye, therebyapproximating natural accommodation.

For example, in response to a created magnetic field, a ring implantedon or in the cornea or limbus and magnetically coupled to the inductiongenerator may be configured to constrict in response to the createdmagnetic field. This corneal constriction may serve to increase therefractive power of the cornea. The constriction of the cornea may becaused by a bending of the ring.

The ring may comprise, for example, an ionic-polymeric material havingproperties causing it to bend in response to a voltage being applied tothe material. Thus, the stimulus, such as the induction generator, maybe located proximate to or remote from the implanted ring. For example,the induction generation may be implanted underneath the skin.Optionally, the ring may be encapsulated by a silicon shell, as well ascoated with a collagen film, which may serve as an additional mechanismto adhere the ring via implantation at the surface of the cornea.

Accordingly, embodiments of the present disclosure may be used torestore accommodation, or, in effect, compensate for a lack ofaccommodation of the crystalline lens or implanted IOL in case ofpseudophakia, using an implantable ring in the cornea or limbus that iscontrolled by a stimulus outside the cornea. Specifically, the ring maybe able to contract or relax in a controlled way in order to affect thecurvature of the cornea. By changing the curvature, the ring may alsochange the dioptric power of the cornea, and therefore also the dioptricpower of the eye.

BRIEF DESCRIPTION OF THE FIGURES

Understanding of the present invention will be facilitated byconsideration of the following detailed description of the preferredembodiments of the present invention taken in conjunction with theaccompanying drawings, in which like numerals refer to like parts:

FIG. 1 illustrates a diagram of a human eye;

FIG. 2 illustrates an example of a ring affixed to the eye according toembodiments of the present disclosure;

FIG. 3 illustrates an exploded view of an implantable ring according toembodiments of the present disclosure.

FIG. 4 illustrates a magnetic induction generator according toembodiments of the present disclosure;

FIG. 5(a) illustrates an example of an implanted ring in a relaxed stateaccording to embodiments of the present disclosure;

FIG. 5(b) illustrates an example of an implanted ring in an activatedstate according to embodiments of the present invention; and

FIG. 6 illustrates a method of actively constricting a cornea of a humaneye according to embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is to be understood that the figures and descriptions of the presentinvention have been simplified to illustrate elements that are relevantfor a clear understanding of the present invention, while eliminating,for the purpose of clarity, many other elements found in typicalintraocular devices. Those of ordinary skill in the art may recognizethat other elements and/or steps are desirable and/or required inimplementing the present invention. However, because such elements andsteps are well known in the art, and because they do not facilitate abetter understanding of the present invention, a discussion of suchelements and steps is not provided herein. The disclosure herein isdirected to all such variations and modifications to such elements andmethods known to those skilled in the art.

Embodiments of the present disclosure include an apparatus, system andmethod for constricting a cornea of a human eye. A control deviceexternal to the subject eye may be configured to create a stimulus, suchas a magnetic field, for an implanted ring that, when stimulated, maychange the curvature, and thus the dioptric power, of the eye, therebyapproximating natural accommodation.

More particularly, embodiments may include a magnetic inductiongenerator and an implantable band that together approximate naturalaccommodation, or, in effect, compensate for a lack of accommodation, ofthe crystalline lens or implanted IOL in case of pseudophakia.Specifically, through magnetic induction affected by the magneticinduction generator, the ring may be able to contract or relax in acontrolled way in order to affect the curvature of the cornea. Bychanging the curvature, the ring may also change the dioptric power ofthe cornea, and therefore, also the dioptric power of the eye.

FIG. 1 is a diagram of an eye. Eye 10 includes retina 12 for receivingan image produced by cornea 14 and natural lens 16 from light incidentupon eye 10. Natural lens 16 is disposed within capsular bag 20, whichseparates anterior and posterior parts of eye 10. Capsular bag 20 is aresilient material that changes the shape and/or location of naturallens 16 in response to ocular forces produced when ciliary muscles 22relax and stretch natural lens 16 via zonules 24 disposed about anequatorial region of capsular bag 20.

This shape change effectuated by ciliary muscles 22 may flatten naturallens 16, thereby producing a relatively low optical power for providingdistant vision in an emmetropic eye. To produce intermediate and/or nearvision, ciliary muscles 22 contract, thereby relieving tension onzonules 24. The resiliency of capsular bag 20 thus provides an ocularforce to modify the curvature of natural lens 16, to thereby provide anoptical power suitable for required vision. This modification, oraccommodation, allows for changes of the focus of the eye for differentviewing distances.

An eye affected by presbyopia often loses the ability to rapidly andeasily refocus on objects at varying distances. The ability to focus onobjects at near distances may also be lost. Although the conditionprogresses over the lifetime of an individual, the effects of presbyopiausually become noticeable after the age of 45 years. For example, thecrystalline lens may lose a substantial amount of its elastic propertiesand may have a limited ability to change shape.

To, in effect, compensate for the loss of elastic properties of thecrystalline lens, embodiments of the present disclosure include animplantable ring that may contract or relax in a controlled way in orderto affect the curvature of the cornea. As such, embodiments may serve tocounteract the effects of presbyopia enabling an affected eye to againbe able to change focus for objects at varying distances.

FIG. 2 illustrates the ring 21 implanted in the eye 10 according toembodiments of the present disclosure. The ring 21 may be surgicallyimplanted, such as by suturing, into the anterior surface of the cornea14, and may preferably be centered around an optical axis 23 through thecenter of the cornea 14. Alternatively, analogous to the insertion ofcorneal onlays, the ring 21 may be implanted under a thin outer layer ofcells of the cornea 14 otherwise known as the epithelium (not shown).More specifically, an instrument may be used to create a pocket betweenthe epithelium and the stroma, and the ring may be implanted in thisspace. As a further alternative, the ring may be implanted in thecorneal limbus (not shown), located at the border of the cornea and thesclera.

FIG. 3 shows an exploded view of implantable ring 21 according toembodiments of the present disclosure. In this exemplary embodiment, theimplantable ring 21 includes a receiver for a stimulus from astimulator, i.e., from a control device, that effects a constriction ofthe ring 21. In the exemplary illustration, the ring 21 may comprise anembedded band 33 of ionic polymer-metal composite (IPMC) material whichis suitable to act as an artificial muscle, that is, which constrictsand relaxes, under an applied and removed voltage, respectively. TheIPMC band 33 may be composed of an ionic polymer like Nafion or Flemion,although any ionic polymer material exhibiting artificial musclebehavior may be employed.

To create the applied voltage to control the IPMC band 33, magneticinduction coils 35 (composed of any conducting material as known in theart, e.g., copper) may be wrapped around the band's planar surface. Theimplantable ring 21 (including the IPMC band and coils 35) may beenclosed by connectable ends 37, and the entirety of the ring 21 and theconnectable ends 37 may be enclosed by a silicon shell 39. Theconnectable ends 37 may snap or bond together by any known means, suchas sutures, magnets, bio-compatible adhesive, velcro, or the like.

Optionally, so as to aid in adhesion to the implanted location withrespect to the cornea 14, the implantable ring 21 may also be coatedwith a thin bio-compatible adhesive. For example, the ring may be coatedin a thin collagen film (not shown), which may be composed of gelatin, aglycosaminoglycan such as chondroitan sulfate, and carboxymethylcellulose.

The operation of the implantable ring 21 is such that, when the externalvoltage is applied to the IPMC band 33, cations inside its membranecarry solvent molecules toward the cathode, and the movement createsbending, causing the entire implanted ring 21 to constrict. Thisconstricting exerts a pressure on the cornea 14, thereby altering thecornea's curvature. This change in curvature alters the dioptric powerof the cornea, and therefore, also the dioptric power of the eye.

FIG. 4 shows a magnetic induction generator 41 powered by a battery 43employed to induce the voltage in the magnetic induction coils 35 in theassociated implantable ring 21. Because the magnetic induction coils 35are a component of the device getting its power from a the magneticinduction generator 41 (also known as a primary circuit supplying thevoltage), the magnetic induction coils may be otherwise known as“secondary”. More specifically, as a component switch 45 is closed, avoltage may be induced in “primary” induction coil 47, therebygenerating a magnetic field. This generated magnetic field alters themagnetic environment of the associated secondary magnetic inductivecoils 35, thereby inducing a voltage causing the implantable ring 21 toconstrict.

FIG. 5(a) shows the implantable ring 21 of FIG. 2 around the anteriorsurface of the cornea 14 of the eye in a relaxednon-induced/non-stimulated state. In operation, as shown in FIG. 5(b),under an induced voltage from the external magnetic induction generator41, the implantable ring 21 causes the cornea to change shape resultingin an altered refractive power. This increased refractive power mayserve to compensate for the lack of accommodation of the crystallinelens or implanted IOL in case of pseudophakia. Consequently, theimplantable ring 21 may serve to properly coincide the retina/macularegion with the focal point of the eye 10 for viewing an object 51, thuscorrecting, for example, for presbyopia.

The stimulator, such as the magnetic induction generator 41, may, forexample, be affixed to any portion of the ear of the person wearing theimplanting ring, although the location of the generator should not be solimited. For example, the generators may be located anywhere on theperson's body, or article of clothing. For example, the generators maybe worn as a wristband, headband, or even be configured to take the formof decorative jewelry in the form of earpieces (e.g., earrings orneckwear). Further still, the induction generator 41 may be surgicallyimplanted under the skin in a manner and location so as the person mayconveniently turn on or off the generator 41 by the touch of a finger,for example.

Further, those skilled in the art will appreciate, in light of thedisclosure provided herein, that other stimulus receiver and stimulatorpairs (in addition to the magnetic coupling and voltage pair discussedabove) may be employed to stimulate ring 21, and that such stimulatormay be remotely or locally external to the eye, and may be controlled byany known means, such as manual actuation, voice activation, muscularcues (such as squinting or ciliary muscle activation), or the like.

Of course, those skilled in the art will appreciate that, in light ofthe disclosed embodiments, a magnetic field may lose strength thefurther it is from its primary source. As such, it may be preferable forthe stimulator, such as the magnetic induction generator 41, be locatedin a relatively close proximity to the implanted ring to ensure asufficient stimulus, such as a sufficient voltage, is induced.

It is also important to note that the induced voltage need not remainconstant. Stated differently, the induced voltage may vary or be inducedby a variety of techniques. For example, any change in the magneticenvironment may cause a voltage to be “induced” in the coil. No matterhow the change is produced, the voltage may be generated. This changecould be produced by changing the magnetic field strength, moving amagnet toward or away from the coil, moving the coil into or out of themagnetic field, rotating the coil relative to the magnet, etc.

Further still, the induced voltage may be pre-programmed to produce acertain result, which may translate into a specific dioptric power ofthe cornea. For example, applying a voltage of approximately 1 volt maytranslate to a specific change of 1 diopter. On the other hand, applyinga voltage of approximately 5 volts may result in a larger increase ofrefractive power of the cornea, potentially on the order of 3 diopters.

In light of the above discussion, any of these afore-discussedtechniques to induce a voltage (and program, to the extent possible, aparticular change in refractive corneal power) may be effectuated by theimplementation of a general-purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions (e.g., the adjustment ofthe induced voltage) described may be implemented in hardware, software,firmware, or any combination thereof. If implemented in software, thefunctions may be stored on or transmitted over as one or moreinstructions or code on a computer-readable medium, and preferably on anon-transitory computer-readable medium. Computer-readable mediaincludes both computer storage media and communication media includingany medium that facilitates transfer of a computer program from oneplace to another. A storage medium may be any available medium that canbe accessed by a general purpose or special purpose computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code means in the form ofinstructions or data structures and that can be accessed by ageneral-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, any connection is properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. Disk and disc, as used herein, includes compactdisc (CD), laser disc, optical disc, digital versatile disc (DVD),floppy disk and blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

FIG. 6 illustrates a method 600 for actively constricting a cornea of ahuman eye. The method 600 may include, at step 601, creating a stimulus,such as creating a magnetic field by applying a first voltage. Method600 may further include receiving the stimulus at an implanted ring,such as by inducing a receiving second voltage in accordance with thecreated magnetic field, at step 603. In accordance with the receivedstimulus, step 605 may include constricting the ring implanted to thecornea, wherein the constricting alters the shape of the cornea. Step607 may include increasing the dioptric power of the cornea inaccordance with the corneal constriction.

Although the invention has been described and pictured in an exemplaryform with a certain degree of particularity, it is understood that thepresent disclosure of the exemplary form has been made by way ofexample, and that numerous changes in the details of construction andcombination and arrangement of parts and steps may be made withoutdeparting from the spirit and scope of the invention as set forth in theclaims hereinafter.

The invention claimed is:
 1. A system for actively constricting a corneaof a human eye, the system comprising: an induction generator configuredto create a magnetic field; and a ring implanted in the cornea andmagnetically coupled to the induction generator, the ring configured todirectly constrict the cornea in response to the magnetic field throughmagnetic induction affected by the induction generator, the ring able tocontract or relax in a controlled way in order to affect curvature ofthe cornea which changes dioptric power of the cornea and dioptric powerof the eye.
 2. The system of claim 1, wherein the ring bends in responseto an induced voltage indicated by the magnetic coupling.
 3. The systemof claim 2, wherein the induced voltage comprises a predefined inducedvoltage; wherein the induction generator is pre-programmed to producethe predefined induced voltage comprising at least one of a plurality ofspecific voltages, wherein each one of the plurality of specificvoltages bends the ring to produce a specific dioptric power change ofthe cornea.
 4. The system of claim 1, wherein the ring comprises anionic polymeric material.
 5. The system of claim 1, wherein theinduction generator remotely controls the constriction of the ring. 6.The system of claim 1, wherein the ring comprises a silicon shell. 7.The system of claim 1, wherein the ring is coated with a collagen film.8. The system of claim 1, wherein the ring is implanted in the corneallimbus.
 9. A system for treating presbyopia in a human eye, comprising:a ring implanted in a cornea of the human eye and configured to directlyconstrict the cornea of the human eye in response to a stimulus receivedfrom external to the human eye; and a control device configured togenerate the stimulus and located on a person having the human eye, thering able to contract or relax in a controlled way in order to affectcurvature of the cornea which changes dioptric power of the cornea anddioptric power of the eye.